The underlying principle of hydroponics has been used for hundreds of years as a growing method for plants. Researchers in the 1800's used the technique to determine the essential elements for the growth of plants. Today, there are many hydroponic systems which vary in complexity and cost.
According to a Gallup poll conducted in 1985, there is a trend toward smaller scale gardening by consumers. The gardening suppliers have met the demand by offering new types of containers, special types of seeds and other products designed to make such gardening easier. Factors that are contributing to the trend of container gardening include:
1. The sale of new homes on small parcels of land is expected to increase the trend of container gardening in the years ahead. PA1 2. Smaller gardening areas are easily cared for by the aged. PA1 3. Containers will be used in decorating the one and a half million decks that are added to homes each year. PA1 A water impervious container capable of holding a variable depth of nutrient solution; PA1 a solid container lid with a plurality of apertures through which a multitude of root-impervious tubes or frusto-conical containers can be inserted and supported and which stops visible light from entering the plant holding container by fitting over the container; and PA1 a reusable, root-impervious tube or frusto-conical container which can be of a multitude of lengths, but is preferably 5 to 9 inches long, which has an open top and an opening on the bottom of a diameter equal to less than half of the diameter of the main shaft of the tube, and a plurality of apertures in the side walls of various sizes, preferably 1/4 to 1/2 inches in diameter. The container may have a plurality of vertical foils extending inward from the side wall and downward to the lower end to deter roots from spiraling around the side walls.
Several companies sell gardening kits that target the container gardener. One such company offers a gift product line of gardening containers that are attractively packaged and marketed internationally. The kits wholesale for $6.00, retail for approximately $14.00 and consist of a growing container and medium, garden seeds and instructions.
Scientific supply companies sell a variety of experimental hydroponic kits and experimental plant growing kits that are marketed as educational tools.
A definite market exists for the hydroponic growing kit.
Non-circulating hydroponic systems which have a layer of screen just above the nutrient solution level to encourage rooting development and provide an anchor point for plant support are known. A major disadvantage of those systems for a high density, rapid turnover crop such as leaf lettuce (Lactuca sativa. L.) is the difficulty of managing the nutrient solution level while establishing the transplants.
There are many different non-circulating growing systems that have been developed. The following is a sample of hydroponic systems that can currently be found in patent and literature searches. The sample excludes the many systems offered by laboratory supply companies for sale to professional educators.